Semiconductor device coated with a fluorena-containing polyiimide and a process of preparing

ABSTRACT

A novel fluorine-containing aromatic compound of the formula: ##STR1## wherein X is ##STR2## in which R f  is a perfluoroalkyl group having 1 to 10 carbon atoms, R f , is a perfluoroalkyl group having 1 to 12 carbon atoms, p is an integer of 1 to 3, q is an integer of 0 to 3, r is 0 or 1, s is an integer of 0 to 5 and t is an integer of 0 to 5, 
     Y is X, a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a fluoroalkyl group having 1 to 8 carbon atoms, and 
     each A is independently ##STR3##  in which D is an amino, carboxyl, hydroxyl, methyl or haloformyl group, and n is an integer of 1 or 2, or ##STR4## can be used to derive various compounds, some of which are useful for preparing a fluorine-containing epoxy compound or polyimide with good properties.

This application is a divisional of copending application Ser. No.07/521,449 , filed on May 10, 1990, now U.S. Pat. No. 5,166,365, whichis a divisional of application Ser. No. 07/177,446 filed Apr. 4, 1988,now U.S. Pat. No. 4,946,935 the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fluorine-containing aromaticcompound, a process for preparing the same and use thereof.

2. Description of the Related Art

Some aromatic compounds comprising two benzene rings and twotrifluoromethyl groups are known. For example, U.S. Pat. No. 3,959,350discloses a compound of the formula: ##STR5## J. Polym. Sci., B-3, 1021(1965) discloses a compound of the formula: ##STR6##

These known compounds are useful as starting materials in the productionof fluorine-containing epoxy resins and fluorine-containing polyimides.

However, a compound of the formula (1) or (2) in which at least one ofthe trifluoromethyl groups is replaced with a perfluoroalkyl grouphaving at least two carbon atoms has not been known. This may be becausereplacement of trifluoromethyl group with the perfluoroalkyl grouphaving at least two carbon atoms is very difficult due to sterichindrance.

Hitherto, as a fluorine-containing epoxy resin, a polymer of an epoxideof the formula: ##STR7## is known (cf. J. Polym. Sci., B-3, 1021(1965)). The cured product of this polymer has a refractive index n_(D)²³ of 1.524 to 1.527. When an epoxy resin is used as an adhesive for aquartz optical fiber, it is advantageous that the adhesive has arefractive index as close as possible to that of the quartz (n_(D) ²³=1.46). Therefore, the epoxy resin (3) is not satisfactory as anadhesive for optical parts or elements such as the quartz optical fiberand an optical connector.

Polyimide resins are known to have good heat resistance and electricinsulation property, and used as flexible substrates for printedcircuits, a protective coating for various elements, an adhesive forbonding a chip to a substrate and the like. However, the conventionalpolyimide is highly hygroscopic. Therefore, it causes corrosion in theseapplications and its adhesiveness decreases. To improve thehygroscopicity of olyimide, fluorine-containing polyimides comprisingrepeating units of the following formula are proposed: ##STR8##(Japanese Patent Publication No. 1876/1968) and ##STR9## (AlesTransaction, 27, 189 (1984)).

Although these fluorine-containing polyimides have less hygroscopicitythan the conventional polyimides, they still absorb about 0.5 to 1.0% ofwater. Therefore, a polyimide having much less hygroscopicity has beendesired.

In order to improve moisture resistance of a semiconductor device and toprevent software errors caused by alpha-ray, it is known to provide aprotective coating of a polyimide resin on a surface of thesemiconductor device. Also, a semiconductor device having multilayerwiring in which the polyimide layer is provided between the adjacentlayers is known. However, as described above, since the conventionalpolyimide has large hygroscopicity, the device tends to be corroded oradhesiveness is deteriorated. Practically, the corrosion or thedeterioration of adhesiveness results in corrosion breaking of analuminum or copper wire used for wiring of LSI, blister of an insulatinglayer by abrupt heating during solddring or in a bonding step, andleakage current in case where the polyimide is used as a surfacestabilizing layer on an exposed end of PN junction. Then, it has beenproposed to use a fluorine-containing polyimide having improvedhygroscopicity as a protective film for the semiconductor device. Forexample, Japanese Patent Kokai Publication No. 177659/1985 discloses amethod for producing a semiconductor device comprising applying apolyamic acid which is prepared by reacting dianhydride of atetracarboxylic acid of the formula: ##STR10## and a diamine of theformula: ##STR11## and then curing the polyamic acid.

By the above method, the hygroscopicity is not satisfactory and theproblems caused by hygroscopicity are not solved.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a novelfluorine-containing aromatic compound comprising at least onesubstituent having a perfluoroalkyl group of two or more carbon atoms,which substituent is bonded to a carbon atom to which two benzene ringsare bonded.

Another object of the present invention is to provide afluorine-containing epoxy resin which is useful as an adhesive foroptical parts such as quartz optical fibers and optical connectors.

A further object of the present invention is to provide afluorine-containing polyimide having less hygroscopicity than theconventional polyimides and improved heat resistance.

A yet another object of the present invention is to provide asemiconductor device which has high moisture resistance and can overcomethe problems which are found in the conventional semiconductor device.

DETAILED DESCRIPTION OF THE INVENTION

A novel fluorine-containing aromatic compound of the present inventionis represented by the formula: ##STR12## wherein X is ##STR13## in whichR_(f) is a perfluoroalkyl group having 1 to 10 carbon atoms, R_(f) ' isa perfluoroalkyl group having 1 to 12 carbon atoms, p is an integer of 1to 3, q is an integer of 0 to 3, r is 0 or 1, s is an integer of 0 to 5and t is an integer of 0 to 5,

Y is X, a hydrogen atoms, an alkyl group having 1 to 8 carbon atoms or afluoroalkyl group having 1 to 8 carbon atoms, and

each A is independently ##STR14## in which D is an amino, carboxyl,hydroxyl, methyl or haloformyl group and n is integer of 1 or 2, or##STR15## Among the novel fluorine-containing aromatic compound (I) ofthe present invention, that having a methyl group(s) or a hydroxygroup(s) on the benzene ring may be prepared by reacting a compound ofthe formula:

    XCOY                                                       (II)

wherein X and Y are the same as defined above with a compound of theformula:

    A--H                                                       (III)

wherein A is the same as defined above in the presence of a Lewis acid.

Specific examples of the compound (II) are:

C₈ F₁₇ CH₂ CH₂ COCF₃

C₃ F₇ OC(CF₃)FCH₂ CH₂ COCF₃

C₄ F₉ CH₂ CH₂ COCF₃

C₈ F₁₇ CH₂ CH₂ COH

C₈ F₁₇ CH₂ CH₂ COCH₂ CH₂ CF₂ CH₂ (OCF₂ CF₂ CF₂)_(n) F (n is 1 to 5)

H(CF₂ CF₂)₃ CH₂ CH₂ COCF₃

H(CF₂ CF₂)CH₂ CH₂ COCH₂ CH₂ C₈ F₁₇

Specific examples of the compound (III) are toluene, o-xylene, phenoland catechol.

Since the reaction of the compounds (II) and (III) is an electrophilicsubstitution, any compound having an electron-donor group can be used asthe compound (III). By an analogous reaction, an aromatic compoundhaving an electron-donor group or no substituent may be prepared.

The compound (II) may be prepared by a Grignard reaction according tothe following reaction formula: ##STR16## wherein R_(f), R_(f) ', P, q,r, s and t are the same as defined above.

Preferably, two or more equivalents of the compound (III) is reactedwith one equivalent of the compound (II).

The reaction is carried out in the presence of a Lewis acid. Examples ofthe Lewis acid are hydrogen fluoride, aluminum chloride, iron (III)chloride, zinc chloride, boron trifluoride, HSbF₆, HAsF₆, HPF₆, HBF₄,etc. Among them, hydrogen fluoride is preferred.

An amount of the Lewis acid to be used is from 15 to 100 moles,preferably 20 to 50 moles per mole of the compound (II).

The reaction is preferably carried out in the presence of a solvent.Examples of the solvent are dimethylformamide (DMF),hexamethylphosphoramide (HMPA), dimethylacetoamide (DMAc),N-methylpyrolidone, 1,1,2,2-tetrachloro-1,2-difluoroethane,dimethylsulfoxide (DMSO), tetrahydrofuran (THF) and the like. Hydrogenfluoride used as the Lewis acid may act as a solvent.

The reaction temperature is usually from 50 to 200° C., preferably from70° to 150° C. The reaction pressure is usually from 5 to 20 kg/cm²,preferably from 7 to 15 kg/cm². The reaction time varies with otherreaction conditions such as the reaction temperature, and is usuallyfrom 1 to 24 hours.

The reaction product may be recovered from the, reaction mixture by aper se conventional method. For example, the reaction product isextracted with a suitable solvent such as trichlorotrifluoroethane andchloroform and the solvent is evaporated off from the extract to leavethe reaction product.

Among the novel fluorine-containing aromatic compound (I) of the presentinvention, one having carboxyl groups on the benzene rings can beprepared by oxidizing the compound of formula: ##STR17## wherein X, Yand n are the same as defined above, which is prepared by the abovereaction.

The oxidation can be effected by a per se known oxidizing agent such asnitric acid, nitrous acid, chromic acid, permanganic acid, chloric acid,etc. The oxidation is preferably effected at a temperature of 140° to200° C., more preferably from 170° to 190° C. for 0.5 to 10 hours,preferably for 2 to 4 hours.

Among the novel fluorine-containing aromatic compound (I) of the presentinvention, one having amino groups on the benzene rings can be preparedby reacting a compound of the formula: ##STR18## wherein X, Y and n arethe same as defined above with hydrazoic acid in the presence of astrong acid.

An amount of hydrazoic acid to be used is 1 to 2 moles per mole of thecompound (V).

Examples of the strong acid are sulfuric acid, hydrochloric acid, nitricacid, etc. An amount of the strong acid is 20 to 50 equivalents perequivalent of the compound (V).

This reaction is carried out at a temperature of 40° to 60° C.,preferably 50° to 60° C. for 1 to 10 hours, preferably for 2 to 4 hours.Preferably, the reaction is carried out in the presence of a solventsuch as chloroform.

Among the novel fluorine-containing aromatic compound (I) of the presentinvention, an anhydride of the formula: ##STR19## wherein X and Y arethe same as defined above is prepared by dehydrating the tetracarboxylicacid of the formula: ##STR20## wherein X and Y are the same as definedabove which is prepared by the above described process.

This dehydration is effected, under reduced pressure or in a stream ofnitrogen gas, at a temperature of 100° to 200° C., preferably 140° to180° C. When the reduced pressure is applied, a pressure is from 10 to200 mmHg, preferably from 20 to 100 mmHg. The dehydration may be carriedout in the presence of a solvent. In such case, a solution of the abovetetracarboxylic acid is heated up to a boiling point of the solvent.Examples of the solvent are toluene, xylene, chlorobenzene, n-octane,1,1,1,2-tetrachloroethane, 1,1,2,2-teterachloroethane and the like.

Among the novel fluorine-containing aromatic compound (I) of the presentinvention, one having the chloroformyl groups on the benzene rings canbe prepared by reacting the compound (V) with phosphorus pentachloride,phosphorus trichloride or thionyl chloride. In this reaction, thechlorinating agent is used in an amount equal to or more thanequivalent. The reaction is carried out while cooling since it is anexothermic reaction, although it may be carried out while heating. Thereaction is carried out in the absence or presence of a solvent.Examples of the solvent are chloroform, benzene, petroleum ether and thelike. The reaction product can be recovered by rectification.

Among the novel fluorine-containing aromatic compound (I) of the presentinvention, one having the bromoformyl groups on the benzene rings can beprepared by reacting the compound (V) with phosphorus pentabromide orphosphorus tribromide. The reaction conditions are substantially thesame as in the preparation of the compound (I) having the chloroformylgrouos.

The novel fluorine-containing aromatic compound (I) of the presentinvention is useful as a monomer of various polymers. By polymerizingthe compound (I), polyamide, polyimide, polyarylate, epoxy resin,polyester, polycarbonate and the like can be produced according to thekinds of the substituents. Since the polymer comprising the compound (I)has a large fluorine content, they have good weather resistance and lowhygroscopicity.

From the novel fluorine-containing aromatic compound (I), a novelfluorine-containing epoxy compound is produced. The novelfluorine-containing epoxy compound is represented by the formula:##STR21## wherein X and Y are the same as defined above and n is anumber of 0 to 30.

The epoxy compound may be a liquid or solid depending on apolymerization degree.

The novel epoxy resin of the present invention can be prepared byreacting a phenol compound of the formula: ##STR22## wherein X and Y arethe same as defined above with epichlorohydrin.

The compound (VI) is prepared by reacting the compound (II) with aphenol.

In the former reaction, epichlorohydrin is used in an amount of 10 to 30moles per mole of the compound (VI). This reaction is carried out byheating a mixture of the compound (VI) and epichlorohydrin in thepresence of sodium hydroxide at a temperature of 80° to 90° C. whilestirring. The reaction product is recovered by evaporating excessepichlorohydrin off under reduced pressure and filtering off aby-produced sodium chloride.

The fluorine-containing epoxy compound having a large molecular weight,namely the epoxy resin of the present invention can be cured by a methodfor curing the conventional epoxy resin. For example, a curing agent isadded to the epoxy resin and kept standing at a temperature of 5° to200° C. for 10 minutes to 10 hours. Examples of the curing agent arealiphatic diamines (e.g. polymethylenediamine, polyetherdiamine, etc.),straight or branched aliphatic polyamines (e.g. diethylenetriamine,diethylaminopropylamine, animoethylethanolamine, etc.), alicyclicpolyamines (e.g. menthanediamine, isophoronediamine,N-aminoethylpiperazine, etc.), modified amines (e.g. adducts ofethylenetetramine), aromatic diamines (e.g. m-phenylenediamine,4,4'-methylenedianiline, diaminodiphenylether, diaminodiphenylsulfone,etc.), secondary amines (e.g. N-methylpiperazine, piperidine, etc.),tertiary amines (N,N'-dimethylpiperazine, triethanolamine,benzyldimethylamine, etc.), boron trifluoride-monomethylamine complex,low molecular weight compounds of melamine resin or sulfide resin, andanhydrides (e.g. phthalic anhydride, chlorendic anhydride, etc.). Thecuring agent is used in an amount of 0.1 to 10 equivalents, preferably0.5 to 3 equivalents per equivalent of the epoxy groups in thefluorine-containing epoxy resin of the present invention.

Alternatively, the fluorine-containing epoxy resin of the presentinvention containing an initiator which generates a cationic species byirradiation of ultraviolet light can be cured by irradiation ofultraviolet light. Examples of such initiator are diazonium salts (e.g.p-methoxybenzenediazonium hexaflucrophosphate, p-chlorobenzenediazoniumhexafluorophosphaze, etc.), diaryliodonium salts (e.g. diphenyliodoniumhexafluorophosphate, 4,4-di-tert.-butylphenyliodoniumhexafluorcphosphate, etc.) and triarylsulfonium salts (e.g.diphenyl-4-thiophenoxyphenyl sulfonium, etc.).

The fluorine-containing epoxy resin of the present invention has a largefluorine content and in turn good heat resistance, moisture resistance,tracking resistance and weather resistance. Thus, it is useful as anadhesive, a coating material, a molding material and the like.Particularly, it is used as an adhesive for bonding the optical partssuch as the ouartz optical fiber or the optical connector since itsrefractive index after cured is close to that of the quartz.

From the novel fluorine-containing aromatic compound (I), a novelfluorine-containing polyimide is prepared. It is represented by theformula: ##STR23## wherein R¹ is a residue which is formed by removingtwo acid anhydride groups from an aromatic tetracarboxylic anhydride, R²is a residue which is formed by removing two amino groups from anaromatic diamine provided that at least one of R¹ and R² contains agroup of the formula: ##STR24## wherein X and Y are the same as definedabove, and n is an integer not smaller than 10.

One of the characteristics of the fluorine-containing polyimide of thepresent invention resides in that the group of the formula: ##STR25##wherein X and Y are the same as defined above is present between twoaromatic rings. Therefore, at least one of R¹ and R² should contain thisgroup. That is, R¹ should be, for example, a group of the formula:##STR26## and/or R² should be, for example, a group of the formula:##STR27##

In addition to the above group, exampls of R¹ includes: ##STR28##wherein R³ is --O--, --CO--, --SO₂ --, --C(CH₃)₂ --, --C(CF₃)₂ --,##STR29## wherein R⁴ is --C₆ H₄ --, --C₆ H₄ O--C₆ H₄ -- or --C₆ H₄--O--C₆ H₄ --O--C₆ H₄ --, ##STR30## wherein R⁵ is --O--, --O--(CH₂)₄--O--, --O--(CH₂)₆ --O--, ##STR31##

In addition to the above group, examples of R² include: ##STR32##wherein R⁶ is --O--, --CO--, --S--, --CH₂ --, --C(CH₃)₂, --C(CF₃)₂ --,--SO₂ --, ##STR33## or --Si(CH₃)₂ --, and ##STR34## wherein R⁷ is --O--,--SO₂ --, --CH₂ --, --CO--, --C(CH₃)₂ -- or --S--.

The fluorine-containing polyimide of the present invention may beprepared by reacting an aromatic diamine of the formula:

    H.sub.2 N--R.sup.2 --NH.sub.2

wherein R² is the same as defined above with an aromatic tetracarboxylicanhydride of the formula: ##STR35## wherein R¹ is the same as definedabove to obtain a polyamide acid of the formula: ##STR36## wherein R¹and R² are the same as defined above, and n is an integer not smallerthan 10, and then converting the polyamic acid to the polyimide.

In the combination of the aromatic diamine and the aromatictetracarboxylic anhydride, when an aromatic diamine other than thediamine of the formula: ##STR37## wherein X and Y are the same asdefined above is used, the aromatic tetracarboxylic anhydride should beone having the formula: ##STR38## wherein X and Y are the same asdefined above. When an aromatic tetracarboxylic anhydride other than theanhydride (VIII), the aromatic diamine (VII) should be used as thediamine element.

The aromatic diamine (VII) may be parpared by reacting the compound (II)with toluene in the presence of the Lewis acid to obtain a compound ofthe formula: ##STR39## wherein X and Y are the same as defined above,oxidizing this compound and reacting the oxidized compound with hydrogenazide. The anhydride (VIII) may be prepared by reacting the compound(II) with o-xylene in the presence of the Lewis acid to obtain acompound of the formula: ##STR40## wherein X and Y are the same asdefined above, oxidizing the resulting compound and then thermallydehydrating it.

Other examples of the aromatic diamine are 4,4'-diaminodiphenyl ether,3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether,4,4'-diaminodiphenyl thioether, 3,3'-diaminodiphenyl thioether,3,4'-diaminodiphenyl thioether, 4,4'-diaminobenzophenone,3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone,4,4'-diaminodiphenylsulfone, 3,3'-diphenylsulfone, 3,4'-diphenyisulfone,4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane,3,4'-diaminodiphenylmethane, 2,2'-bis(4-aminophenyl)propane,2,2'-bis(3-aminophenyl)propane, benzidine, 3,3'-diaminobiphenyl,3,4'-diaminobiphenyl, p-phenylenediamine, m-phenylenediamine,bis(4-amino)dimethylsilane, bis(4-aminophenyl)diethylsilane,bis(4-aminophenyl)diphenylsilane and the like.

Other examples of the aromatic tetracarboxylic anhydride are pyromeliticdianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydridei,3,3',4,4'-diphenyl tetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2',3,3'-diphenyl tetracarboxylicdianhydride, 2,3',3,4'-diphenyl tetracarboxylic dianhydride,2,21-bis-(3,4-dicarboxyphenyl)propane dianhydridepbis(3,4-dicarboxy)phenyl sulfone dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride,catelene-1,4,5,8-tetracarboxylic dianhydride,2,2-bis(2,3-dicarboxyphenyl)propane dianhydride,1,1-bis-(2,3-dicarboxyphenyl)ethane dianhydride,1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride,bis(2,3-dicarboxyphenyl)-methane dianhydride,bis(3,4-dicarboxyphenyl)methane dianhydride,bis(3.4-dicarboxyphenyl)thioether dianhydride, 3,4,3',4'-benzophenonetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)dimethylsilanedianhydride, bis(3,4-dicarboxyphenyl)diphenylsilane dianhydride and thelike.

The aromatic anhydride and the aromatic diamine are reacted in anequimolar amount in the presence of a solvent while stirring. Thereaction temperature is from 0° to 60° C., preferably from 20° to 40°C., and the reaction time is from 1 to 24 hours, preferably from 3 to 12hours. Specific examples of the solvent are N-methyl-2-pyrolidone (NMP),dimethylacetoamide (DMAc), dimethylformamide (DMF), sulforan,tetrahydrofuran etc. When the aromatic diamine (VII) and the aromaticanhydride (VIII) are reacted, preferably used solvent arehologen-containing solvents such as tetrachlorohexafluorobutane,trichlorotrifluoroethane, tetrachlorodifluoroethane andperchloroethylene.

The polyamis acid can be converted to the polyimide by a per seconventional method. For example, the polyimide acid is easily convertedto the polyimide by heating the former at a temperature not lower than200° C., preferably from 230° to 400° C.

According to the present invention, the polyamic acid is coated on thesemiconductor device and a lead wire and then heated to cure.

The present invention will be explained further in detail by thefollowing Examples.

Reference Example

In a 5 l four-necked flask equipped with a reflux condenser, athermometer, a nitrogen-introducing tube and a stirrer, metal magnesium(24.31 9, 1 mol), absolute diethyl ether (150 ml) and a small amount ofiodine crystal were charged and stirred with introducing nitrogen. C₈F₁₇ CH₂ CH₂ I (574 g, I mol) dissolved in diethyl ether (600 mi) wasdropwise added. After finishing the addition, a reaction solution washeated to reflux for 2 hours. After cooling the reaction solution to aroom temperature, CF₃ CO₂ CH₃ (128 g, 1 mol) was dropwise added. Thenthe reaction solution was stirred for two hours.

After the reaction finished, an aqueous sulfric acid solution was addedto acidify the reaction solution. A diethyl ether layer was washed withwater three times, dried over anhydrous sodium sulfate and then withphosphorous pentoxide. The diethyl ether layer was distilled underreduced pressure to give a ketone compound, C₈ F₁₇ CH₂ CH₂ CO--CF₃.Yield: 174 g (32%). Boiling point: 96°-98° C./17 mmHg.

IR (NaCl): ν(cm⁻¹)=1,780, 1,250, 1,210, 1,150, 1,010

¹⁹ F-NMR (CCl₄) δ(ppm) : -12.7 (s, 3F), 35.9 (broad, 2F), 43.2 (broad,6F), 44.0 (broad, 2F), 44.3 (broad, 2F), 47.5 (broad, 2F)

Example 1

In a 300 ml autoclave, toluene (15.2 g, 0.165 mol), C₈ F₁₇ CH₂ CH₂ COCF₃(40.9 g, 0.075 mol) obtained in Reference Example and hydrogen fluoride(40 ml) were charged and reacted at 90°-100° C. under 9 kg/cm² for 18hours with stirring.

After the reaction finished, hydrogen fluoride was removed and areaction product was extracted with trichlorotrifluoroethane.Trichlorotrifluoroethane was distilled off from an extract under areduced pressure to give a compound of the formula: ##STR41## Yield:38.9 (73%).

IR (NaCl): ν(cm⁻¹)=2,900, 1,520, 1,465, 1,330, 1,240, 1,210, 1,150,1,010, 815, 730, 710

¹ H-NMR (CCl₄ /TMS): δ(ppm)=1.5-3.3 (m, 4H), 2.30 (s, 6H), 7.05 (s, 8H)

¹⁹ F-NMR (CCl₄ /TFA): δ(ppm)=-12.2 (s, 3F), 2.8 (t, 3F), 36.3 (broad,2F), 43.5 (broad, 6F), 44.4 (broad, 2F), 44.7 (broad, 2F), 47.9 (broad,2F)

Example 2

In a 100 ml autoclave, the compound (20.0 g, 0.028 mol) of the formula:##STR42## obtained in Example 1 and acetic acid (73 ml) were charged.Chromium (VI) oxide (18.3 g) was added to a reaction mixture withstirring at 80° C. The reaction mixture was stirred for 12 hours withkeeping a temperature at 80°-90° C.

After the reaction finished, acetic acid was distilled off from thereaction mixture under a reduced pressure. An 5% aqueous sodiumhydroxide solution (400 ml) was added to dissolve a residual solid. Thesolution was filtered to separate chromium (III) oxide. An aqueoussodium sulfate solution was added to the filtrate to precipitate a whitesolid, which was filtered and dried to give a compound of the formula:##STR43## Yield, 18.5 g (86%).

IR (KBr): ν(cm⁻¹)=3,000, 1,700, 1,615, 1,425, 1,330, 1,285, 1,240,1,200, 1,150, 1,120, 1,010, 855, 810, 780, 725, 710

¹ H-NMR (DMSO-d₆ /TMS): δ(ppm)=1.6-3.1 (m, 4H), 7.57 (dd, J=8 Hz, 577Hz, 8H), 9.5-0.5 (broad, 2H)

¹⁹ F-NMR (DMS_(O) -d₆ /TFA): δ(ppm)=-13.0 (s, 3F), 2.1 (t, 3F), 35.9(broad, 2F), 43.0 (broad, 6F), 44.0 (broad, 2F), 44.3 (broad, 2F), 47.3(broad, 2F)

Example 3

In a 500 ml three-necked flask, the compound (15.0 g, 0.0195 mol) of theformula: ##STR44## obtained in Example 2, concentrated sulfuric acid (63g) and chloroform (200 mi) were charged. 1N hydrazoic acid (58.5 ml)vias dropwise added to reflux for two hours with heating at 50° C.

After the reacti-cn finished, the reaction solution vias cooled zc aroom temz)erature and poured in water (400 ml) to make a oreci-sitate.The precipitated was filtered, and an acueous sodium hydroxide solutionwas added to make it alkaline. The mixture was extracted with chloroform(500 ml). The extract was evaporated to give a compound of the formula:##STR45##

Yield, 8.34 g (60%).

IR (KBr): ν(cm⁻¹)=3,450, 3,370, 1,630, 1,520, 1,370, 1,335, 1,280,1,250, 1,230, 1,200, 1,150, 1,110, 1,005, 960, 825, 820, 705

¹ H-NMR (CDCl₃ /TMS): δ(ppm)=1.5-2.9 (m, 4H), 3.62 (s, 4H), 6.72 (dd,J=8 Hz, 37Hz, 8H)

¹⁹ F-NMR (CDCl₃ /TFA): 6 (ppm) -12.2 (s, 3F), 2.1 (t, 3F), 35.7 (broad,2F), 43.0 (broad, 6F), 44.0 (broad, 2F), 44.3 (broad, 2F), 44.3 (broad,2F), 47.3 (broad, 2F)

Example 4

In a 100 nl autoclave, o-xylene (17.1 9, 0.1617 mol), C₈ F₁₇ CH₂ CH₂COCF₃ (40.0 g, 0.0735 mol) and hydrogen fluoride (37 ml) were chargedand reacted at 90°-100° C. under 9 kg/cm² for 18 hours with stirring.

After the reaction finished, the resultant mixture was extracted withtrichlorotrifluoroethane. Trichlorotrifluoroethane was distilled offfrom the extract under a reduced pressure to give a compound of theformula: ##STR46## Yield, 38.3 g (70%).

IR (KBr):ν(cm⁻¹)=2,950, 1,510, 1,470, 1,450, 1,375, 1,330, 1,200, 1,145,1,110, 1,020, 990, 965, 880, 820, 735, 710

¹ H-NMR (CC1₄ /TMS): δ(ppm)=1.6-3.1 (m, 4H), 2.22 (s, 12H), 6.94 (s, 6H)

Example 5

In a 500 ml autoclave, a compound (38.0 g, 0.05 mol) of the formula:##STR47## obtained in Example 4, 60% nitric acid (58 ml) and water (57ml) were charged and reacted at 170°-180° C. for 2 hours.

After the reaction finished, a reaction mixture was filtered to separatea solid idroduct. An 5% aqueous sodium hydroxide solution was added toche silid product to dissolve it and filtered. Aqueous sulfric acidsolution was added to acidify the filtrate and extracted with ether.Ether was distilled off from the extract to give a compound of theformula: ##STR48## Yield: 39.7 g (90%).

IR (KBr): ν(cm⁻¹)=3,400, 3,000, 1,710, 1,615, 1,580, 1,510, 1,425,1,210, 1,160, 1,110, 1,070, 1,020, 980, 820, 800, 725, 705

¹ H-NMR (acetone-d₆ /TMS): δ(ppm)=1.7-3.3 (m, 4H), 6.6-7.6 (broad, 4H),7.6-8.0 (m, 6H)

¹⁹ F-NMR (acetone-d₆ /TFA): δ(ppm)=-11.5 (s, 3F), 3.6 (t, 3F), 36.9(broad, 2F), 44.3 (broad, 6F), 45.2 (broad, 2F), 45.5 (broad, 2F), 48.6(broad, 2F)

Example 6

In a 200 ml eggplant flask, the compound (39.7 g, 0.046 mol) of theformula: ##STR49## and heated at a temperature of 150°-160° C. for 6hours.

Thereafter, the reaction product was removed from the eggplant flask andrecrystallized from ether to give a white crystalline compound-of theformula: ##STR50## Yield: 22.7 g (60%).

IR (KBr): ν(cm⁻¹)=1,860, 1,780, 1,620, 1,490, 1,470, 1,435, 1,400,1,375, 1,335, 1,205, 1,180, 1,155, 1,120, 1,015, 900, 740, 725, 700

¹ H-NMR (hot CDCl₃ /TMS): δ(ppm)=1.6=3.2 (m, 4H), 7.5-8.1 (m, 6H)

¹⁹ F-NMR (hot CDCl₃ /TFA): δ(ppm)=-13.2 (s, 3F), 2.1 (t, 3F), 35.8(broad, 2F), 43.0 (broad, 6F), 44.0 (broad, 4F), 47.2 (brcad, 2F)

Example 7

In a 100 ml autoclave, phenol (15.2 g, 0.162 mol), C₈ F₁₇ CH₂ CH₂ COCF₃(40.0 g, 0.0735 mol) obtained in Example 6 and hydrogen fluoride (37 ml)were charged and reacted at temperature of 85°-90° C. under pressure of9 kg/cm² for 15 hours with stirring.

After the reaction finished, hydrogen fluoride was removed to give ayellcw solid product (49.6 g). The product was recrystallized fromtetrafluoropropanol to give a white crystalline product of the formula:##STR51## Yield: 31.8 g (70%).

IR (KBr): ν(cm⁻¹)=3,350, 1,610, 1,600, 1,515, 1,460, 1,440, 1,350,1,250, 1,210, 1,155, 1,110, 1,005, 830, 700

¹ H-NMR (acetone-d₆ /TMS): δ(ppm)=1.7-3.2 (m, 4H), 6.95 (dd, J=8 Hz, 28Hz, 8H), 8.35 (s, 2H)

¹⁹ F-NMR (acetoned-d₆ /TFA): δ(ppm)=-12.2 (s, 3F), 2.2 (t, 3F), 35.9(broad, 2F), 44.2 (broad, 6F), 44.3 (broad, 4F), 47.5 (broad, 2F)

Example 8

In a 500 ml autoclave, phenol (20.6 g, 0.22 mol), C₃ F₇ OCF(CF₃)CH₂ CH₂COCF₃ (41.0 g, 0.1 mol) obtained in Reference Example and hydrogenfluoride (50 g, 2.5 mol) were charged and reacted at temperature of80°-84° C. for 15 hours with stirring.

After the reaction finished, the reaction solution was poured in an icedwater. Hydrogen fluoride was removed by decantation to give a highlyviscous liquid. The liquid was extracted with diethyl ether (300 ml) andthe extract was neutralized with sodium hydrogen carbonate, and washedwith water twice. Then, the extract was dried over sodium sulfate andether was distilled off from the extract to give a compound of theformula: ##STR52## Yield: 34.1 g (59%). Boiling point: 203°-205°C./1mmHg.

IR (KBr): ν(cm⁻¹)=3,360, 1,615, 1,605, 1,520, 1,440, 1,340, 1,305,1,230, 1,200, 1,160, 1,090, 1,010, 975, 840, 750

¹ H-NMR (DMSO-d₆ /TMS): δ(ppm)=1.5-3.0 (m, 4H), 6.82 (dd, J=8Hz, 24 Hz,8H), 9.42 (s, 2H)

¹⁹ F-NMR (DMSO-d₆ /TFA): δ(ppm)=-12.2 (s, 3F), 2.9 (m, 5F), 4.7 (d, 3F),51.3 (m, 3F)

Example 9

In a 500 mi autoclave, toluene (60.81 g, 0.66 mol), C₄ F₉ CH₂ CH₂ COCF₃(103.23 g, 0.3 mol) and hydrogen fluoride (150 g) %vere charged andreacted at temperature of 85°-90° C. with stirring.

After the reaction finished, a reaction mixture was extracted withtrichlorotrifluorcethane. Trichlorotrifluoroethane was distilled offfrom the extract to give a compouna of the formula: ##STR53## Yield:127.7 g (83%).

IR (KBr): ν(cm⁻¹)=3,000, 1,615, 1,520, 1,465, 1,350, 1,225, 1,135,1,010, 920, 880, 850, 810, 730

¹ H-NMR (CDCl₃ /TMS): δ(ppm)=1.7-2.9 (m, 4H), 2.35 (s, 6H), 7.17 (s, 8H)

¹⁹ F-NMR (CDCl₃): δ(ppm)=-12.3 (s, 3F), 2.7 (t, 3F), 36.4 (m, 2F), 47.6(t,2F)

Example 10

In a 100 ml autoclave, the compound (105.0 g, 0.206 mol) of the formula:##STR54## 60% nitric acid (128 ml) and water (126 ml) were charged andreacted at temperature of 180°-190° C. with stirring.

After the reaction finished, a reaction product was filtered to separatea solid product. An 5% aqueous sodium hydroxide (400 ml ) was added tothe solid product, and undissolved materials were filtered off. Anaqueous sulfric acid solution was added to acidify the filtrate toprecipitate a white solid, which was separated by filtration and drivedto give a compound of the formula: ##STR55## Yield: 112.4 g (96%).

IR (KBr): ν(cm⁻¹)=3,000, 1,615, 1,520, 1,465, 1,350, 1,225, 1,135,1,010, 920, 880, 850, 810, 730

¹ H-NMR (CDCl₃ /TMS): δ(ppm)=1.7-2.9 (m, 4H), 2.35 (s, 6H), 7.17 (s, 8H)

¹⁹ F-NMR (CDCl₃): δ(ppm)=-12.3 (s, 3F), 2.7 (t, 3F), 36.4 (m, 2F), 45.7(m, 2F), 47.6 (t, 2F)

Example 11

In a 2 liter three-necked flask, the compound (64.0 g, 0.112 mol) of theformula: ##STR56## obtained in Example 10, concentrated nitric acid (176g) and chloroform (350 ml) were charged. Then 1.1 N hydrazoic acid (306ml) was dropwise added, and a mixture was heated to temperature of40°-45° C. for 2 hours with stirring. After the mixture was stirred at aroom temperature for 12 hours, a chloroform layer was separated from anaqueous layer. The aqueous layer was made alkaline with sodium hydroxideand extracted with chloroform (400 ml). After the extract was dried oversodium sulfate, chloroform was distilled off and the residue wasrecrystallized from petroleum benzinediethyl ether to give a compound ofthe formula: ##STR57## Yield: 32.8 g (54%).

IR (KBr): ν(cm⁻¹) =3,420, 3,350, 1,620, 1,520, 1,460, 1,360, 1,320,1,280, 1,250, 1,220, 1,200, 1,160, 1,130, 1,020, 1,005, 920, 850, 835,720

¹ H-NMR (DMSO-d₆): δ(ppm)=1.5-3.8 (m, 4H), 5.21 (s, 4H), 6.74 (dd, J=8Hz, 36 Hz, 8H)

¹⁹ F-NMR (DMSO-d₆): δ(ppm)=-12.6 (s, 3F), 2.4 (t, 3F), 35.9 (m, 2F),45.8 (m, 2F), 47.5 (t, 2F)

Example 12

In a 100 ml autoclave, o-xylene (63.0 g, 0.594 mol), C₄ F₉ CH₂ CH₂ COCF₃(92.9 g, 0.27 mol) and hydrogen fluoride (135 g) were charged andreacted at a temperature of 75°-80° C. for 17 hours with stirring.

After the reaction finished, a reaction mixture was extracted withtrichlorotrifluorcethane. Trichlorctrifluoroethane was distilled offfrom an extract to give a compound of the formula: ##STR58## Yield:130.9 g (90%).

IR (NaCl): ν(cm⁻¹)=2,950, 1,620, 1,575, 1,505, 1,450, 1,225, 1,130,1,015, 990, 900, 880, 810, 740, 730, 725, 720, 700

¹ H-NMR (CCl₄): δ(ppm)=1.6-3.9 (m, 4H), 2,23 (s, 12H), 7.00 (s, 6H)

¹⁹ F-NMR (CCl₄): δ(ppm)=-12.4 (s, 3F), 2.9 (t, 3F), 36.6 (m, 2F), 45.9(m, 2F), 47.9 (t, 3F)

Example 13

In a 500 ml autoclave, the compound (80.8 g, 0.15 mol) of the formula:##STR59## obtained in Example 12, 60% nitric acid (166 ml) and water(164 ml) were charged and reacted at temperature of 170°-180° C. for 2hours with stirring.

After the reaction finished, a reaction product was filtered. An 5%aqueous sodium hydroxide solution was add to dissolve a filtered solidand filtered. An aqueous sulfric acid was added to acidify the filtrateand extracted with ether. The extract was distilled to remove ether togive a compound of the formula: ##STR60## Yield: 80.9 g (88%).

IR (KBr): ν(cm⁻¹)=3,000, 1,705, 1,605, 1,570, 1,500, 1,420, 1,230,1,160, 1,130, 1,070, 1,010, 880, 850, 800, 720

¹ H-NMR (DMSO-d₆): δ(ppm)=1.8-3.8 (m,4H), 7.3-7.8 (m,6H), 10-12 (board,4H)

¹⁹ F-NMR (DMSO-d₆): δ(ppm)=-13.2 (s,3F), 2.1 (t,3F), 35.3 (m, 2F), 45.4(m, 2F), 47.2 (t, 2F)

Example 14

In a 200 ml eggplant flask, the compound (86.9 g, 0.132 mol) of theformula: ##STR61## obtained in Example 13 was charged and heated at 160°C. under a reduced pressure for 5 hours.

After heating, a product was removed and recrystallized from ether togive a white crystalline product of the formula: ##STR62## Yield: 60.6 g(65%).

IR (KBr): ν(cm⁻¹)=1,860, 1,785, 1,620, 1,430, 1,330, 1,255, 1,235,1,175, 1,150, 1,130, 1,115, 1,010, 900, 850, 740, 720, 700

¹ H-NMR (DMSO-d₆): δ(ppm)=1.5-3.6 (m, 4H), 7.7-8.2 (m, 6H)

¹⁹ F-NMR (DMSO-d₆): δ(ppm)=-13.3 (s, 3F), 2.3 (t,3F), 35.2 (m, 2F), 45.2(m, 2F), 47.3 (t, 2F)

Example 15

In a 3 l round bottom flask equipped with a thermometer, a stirrer and areflux condenser, a compound (600 g, 0.840 mol) of the formula:##STR63## epichlorohydrin (1166 g, 12.60 mol), pure water (4 ml) andsodium hydroxide (3 g) were charged and heated to 83°-87° C. withstirring until sodium hydroxide solid disappeared. Sodium hydroxide (5 geach) was added repeatedly with keeping a temperature at 83°-87° C. sothat a total amount of sodium hydroxide was 70 g (1.75 mol). Afteraddition of sodium hydroxide and an exothermic reaction finished, areaction mixture was stirred for one hour with keeping the temperatureat 83°-87° C.

After the reaction finished, the reaction solution was distilled under areduced pressure to remove unreated epichlorohydrin, and a residue wascooled to 70° C. Benzene (100 ml) was added and filtered to separate offby-producted sodium chloride. A filtrate was distilled under reducedpressure to remove benzene and to give a liquid epoxy resin of theformula: ##STR64## wherein an average of n is 0.2. Yield: 652 g. A valueof n was determined by means of HPLC (Hih Performance LiquidChromatography).

IR (NaCl): ν(cm⁻¹)=3,000, 1,615, 1,585, 1,520, 1,460, 1,260-1,100,1,030, 1,000, 970, 915, 860, 830, 770, 740, 725, 710

¹ H-NMR (CCl₄): δ(ppm)=6.86 (dd, 9.6H, J=9 Hz, 27 Hz), 4.2-3.7 (m,4.2H), 3.3-3.0 (m, 2.2H), 2.9-2.3 (m, 7.2H), 2.3-1.5 (broad, 2.4H)

¹⁹ F-NMR (CCl₄): δ(ppm)=-12.1 (s, 3F), 2.3 (t, 3F), 35.9 (b, 2F), 43.2(b, 6F), 44.3 (b, 4F), 47.5 (b, 2F)

Example 16

In a 100 ml flask equipped with a thermometer, a stirrer and a refluxcondenser, a compound (14.51 g, 0.025 mol) of the formula: ##STR65##epichlorohydrin (34.70 g, 0.375 mol) and pure water (0.13 g) werecharged and heated to 80°-85° C. Then sodium hydroxide (0.65 g each) wasadded twice with keeping a temperature at 70°-75° C. A total amount ofsodium hydroxide was 2.05 g (0.051 mol). A reaction mixture was stirredfor one hour with keeping the temperature at 80°-85° C.

After the reaction finished, the reaction solution was distilled under areduced pressure to remove unreacted epichlorohydrin. Benzene (15 ml)was added to the residue and filtered to separate off by-produced sodiumchloride. The filtrate was distilled under a reduced pressure to removebenzene and to give a liquid epoxy resin of the formula: ##STR66##wherein an average of n is 0.2. Yield: 16.89 g.

IR (NaCl): ν (cm⁻¹)=2,900, 1,610, 1,580, 1,515, 1,460, 1,330, 1,290,1,240, 1,200, 1,150, 1,080, 1,030, 1,010, 910, 830, 750

¹ H-NMR (CCl₄): δ (ppm)=6.85 (dd, 9.6H, J=9 Hz, 26 Hz), 4.2-3.7 (m,4.2H), 3.3-3.0 ) m, 2.4H), 2.9-2.3 (m, 7.2H), 2.2-1.7 (broad, 2.4H)

¹⁹ F-NMR (CCl₄): δ (ppm)=-12.1 (s, 3F), 2.6 (m, 5F), 4.4 (d, 3F), 51.0(s, 3F)

Experiment

The following properties (1) to (3) of the fluorine-containing epoxyresins obtained in Examples 15 and 16 and those of a fluorine containingepoxy resin (Comparative Example 1) of the formula: ##STR67## weremeasured. The resins were cured under the following conditions:

Curing agent: Epomic Q-694 (manufactured by Mitsui PetrochemicalIndustries, Ltd.)

Ratios of the curing agent: 5parts by weight of the curing agent per 32parts by weight of the resin of Example 15 10 parts by weight of thecuring agent per 47 parts by weight of the resin of Example 16 4 partsby weight of the curing agent per 11 parts by weight of the resin ofComparative Example 1

Curing temperature: 65° C.

Curing time: 6 hours The following properties were measured as follows:

(1) Refractive index

The refractive index is measured at 23° C. by an Abbe's refractometer.

(2) Glass transition temperature (Tg)

(3) Shearing adhesion strength

This is measured according to JIS K-6850 by using SUS-304.

Results of the properties (1) to (3) are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                               Refractive Index (n.sub.D.sup.23)                                                                    Shearing                                                 Before    After       Tg   strength                                  Resin    curing    curing      (°C.)                                                                       (kg/cm.sup.2)                             ______________________________________                                        Ex. 15   1.448     1.462       76   128                                       Ex. 16   1.461     1.481       56   120                                       Comp. 1  1.497     1.527       76   125                                       ______________________________________                                    

The results of Table 1 show that the fluorine-containing epoxy resins ofthe present invention have lower refractive indexes than theconventional fluorine-containing epoxy resin and nearly the same as therefractive index of quartz (n_(D) ²³ =1.46).

Example 17

An aromatic diamine (14.25 g, 0.02 mol) of the formula: ##STR68## wasdissolved in a mixed solvent of dimethylacetamide (35.0 g) andtetrachlorohexafluorobutane (65.0 g). Then, a powdery acid anhydride(16.45 g, 0.02 mol) of the formula: ##STR69## was added and reacted at25° C. for 12 hours with stirring. A mixture containing a polyamic acidin a concentration of 23.5% by weight and having viscosity of 14,000 cps(23° C.) was produced. The polyamic acid mixture was coated on a glassplate and dried in an oven at 80° C. for 20 minutes and at 100° C., 200°C. and 300° C. respectively for 1 hour to give a polyimide film.

An infrared spectrum of the polyimide film was measured. Absorption dueto C=O stretching vibration of an imide group was observed at 1,785 cm⁻¹and 1,720 cm⁻¹.

The following properties of the polyimide film were measured:

(1) Water absorption

A piece of the polyimide film (76.2 mm×25.4 mm) is prepared and dried at50°±3° C. for 24 hours. Then it is cooled in a desiceator and weighed(W₁). The piece is immersed in distilled water at 23°±1° C. for 24hours, removed from the water, wiped with a cloth and weighed (W₂). Thewater absorption A is calculated according to the following equation:##EQU1##

(2) Glass transition temperature (T_(g))

A temperature at which the endothermic behavior begins is measured at atemperature raising rate of 10° C./min by using a DSC II typedifferential scanning calorimeter (manufactured by Perkin-Elmer Co.).

(3) Thermal decomposition temperature (T_(d))

A temperature at which a weight decrease begins is measured at atemperature raising rate of 10° C./min by using a differentialthermogravimetric analyzer DT-30manufactured by Shimadzu Corp.).

Results of the properties measured are shown in Table 2.

Example 18

An aromatic diamine (10.25 g, 0.02 mol) of the formula: ##STR70## wasreacted with an acid anhydride (12.45 g, 0.02 mol) of the formula:##STR71## in the same manner as in Example 17 to give a mixturecontaining a polyamic acid in a concentration of 20.1% by weight andhaving viscosity of 11,000 cps.

Then, a polyimide film was prepared and its properties were measured inthe same manner as in Example 17. Results are shown in Table 2.

Example 19

An aromatic diamine (7.12 g, 0.01 mol) of the formula: ##STR72## wasdissolved in dimethylacetamide (30.0 g). Then powder of pyromelliticanhydride (2.18 g, 0.01 mol) was added and reacted in the same manner asin Example 17 to give a mixture containing polyamic acid in aconcentration of 23.7% by weight and having viscosity of 9,000 cps.

Then, a polyimide film was prepared and its properties were measured inthe same manner as in Example 17. Results are shown in Table 2.

Example 20

Diaminodiphenyl ether (4.00 g, 0.02 mol) was dissolved inN-methyl-2-pyrrolidone (60 g). Powder of an acid anhydride (12.45 g,0.02 mol) of the formula: ##STR73## was added and reacted in the samemanner as in Example 17 to give a mixture containing a polyamic acid ina concentration of 21.5% by weight and having viscosity of 12,000 cps.

Then, a polyimide film was prepared and its properties were measured inthe same manner as in Example 17. Results are shown in Table 2.

Comparative Example 2

An aromatic diamine (1.333 g, 3 mmol) of the formula: ##STR74## wasdissolved in dimethylacetamide (20.0 g). An acid anhydride (1.003 g, 3mmol) of the formula: ##STR75## was added and reacted in the same manneras in Example 17 to give a mixture containing a polyamic acid in aconcentration of 10.5% by weight.

Then, a polyimide film was prepared and its properties were measured inthe same manner as in Example 17. Results are shown in Table 2.

Comparative Example 3

A polyimide having structure unit of the formula: ##STR76## (KAPTON Hmanufactured by Du Pont) was used to prepare a film, and properties weremeasured as in the same manner as in Example 17. Results are shown inTable 2.

                  TABLE 2                                                         ______________________________________                                        Water absorption  T.sub.g T.sub.d IR                                          (%)               (°C.)                                                                          (°C.)                                                                          (cm.sup.-1)                                 ______________________________________                                        Ex. 17  0             183     428   1785, 1720                                Ex. 18  0             219     430   1785, 1730                                Ex. 19  0.1           231     424   1780, 1730                                Ex. 20  0.3           249     425   1785, 1720                                Comp. 2 0.6           310     464   --                                        Comp. 3 2.9           --      546   --                                        ______________________________________                                    

Examples 21 to 24 and Comparative Example 4

In a four-necked flask equipped with a thermometer, a stirrer and anitrogen-introducing tube, a purified diamine (0.1 mol) shown in Table 3was charged followed by the addition of a solvent shown in Table 3 todissolve the amine. Then, a tetracarboxylic dianhydride (0.1 mol) shownin Table 3 was added by portions with stirring. A reaction temperaturewas kept at 25±2° C. After the addition of tetracarboxylic dianhydridewas completed and a homogeneous solution was formed, the solvent wasfurther added so as to adjust a solid content in the reaction mixture to15% by weight. Then, the reaction mixture was kept at 25±2° C. in anitrogen atomsphere and stirred for 24 hours to give a polyamic acidsolution.

The polyamic acid was dropped on an element and lead wires of 256 K bitLSI for D-RAM memory (16 pins), and heated at 80° C., 100° C., 150° C.and 200° C. respectively for one hour, and at 250° C. for 20 minutes toprepare a coating film of a fluorine-containing polyimide on the elementand lead wires. The polyimide film had a thickness of 20 to 60 μm. Theresultant element was sealed with an epoxy resin composition prepared asdescribed hereinafter by a transfer molding (180° C., 1.5 minutes, 75kg/cm²). Then it was post-cured at 185° C. for 5 hours to give asemiconductor device sealed with the resin. One hundred LSI devices ofeach Example were used to determine moisture resistant reliability by apressure cocker tester. Results are shown in Table 4. The moistureresistant reliability is expressed in terms of the number of sealeddevices which default by corrosion of aluminum siiring when the sealeddevices are positioned in a steam atmosphere at 120° C. under 2 atm.

                                      TABLE 3                                     __________________________________________________________________________                             Tetracarboxylic                                      Diamine                  dianhydride          Solvent*                        __________________________________________________________________________    Ex. 21                                                                              ##STR77##                                                                                         ##STR78##           NMP/S-316 (40/60 wt/wt)         Ex. 22                                                                              ##STR79##                                                                                         ##STR80##            NMP/S-316 (80/20 wt/wt)        Ex. 23                                                                              ##STR81##                                                                                         ##STR82##           NMP                             Ex. 24                                                                              ##STR83##                                                                                         ##STR84##           NMP                             Comp. 4                                                                             ##STR85##                                                                                         ##STR86##           Dimethyl- acetamide             __________________________________________________________________________     (Note)*                                                                       NMP: NMethyl pyrrolidone                                                      S-316: A fluorinecontaining solvent manufactured by Daikin Industries Ltd

                  TABLE 4                                                         ______________________________________                                               Time (hours)                                                                  500     1000   1500      2000 2500                                     ______________________________________                                        Ex. 21   0         0      0       0     8                                     Ex. 22   0         0      0       6    19                                     Ex. 23   0         0      0       8    21                                     Ex. 24   0         0      2       15   28                                     Comp. 4  0         3      11      25   42                                     ______________________________________                                    

Preparation of epoxy resin composition for sealing:

With an o-cresol novolac epoxy resin (EOCN-1025 manufactured by NipponKayaku Co. Ltd., epoxy equivalent: 2000) (100 parts by weight), amixture of phenol novolac (PR-52194 manufactured by Sumitomo Durez Co.Ltd, hydroxyl group equivalent: 105) (50 parts by weight), 2-phenylimidazole (2 parts by weight), γ-glycidoxypropyl trimethoxysilane (2parts by weight), fumed silica powder (350 parts by weight) and carbonblack (1 parts by weight) was kneaded at 75°-90° C. by a twin-roll mill,cooled and ground in a flaker to prepare an epoxy resin composition forsealing.

What is claimed is:
 1. A semiconductor device which is coated with afluorine-containing polyimide of the formula: ##STR87## wherein R¹ isselected from the group consisting of ##STR88## wherein R³ is --O--,--CO--, --SO₂, --C(CH₃)₂ --, --C(CH₃)₂ --, ##STR89## wherein R⁴ is --C₆H₄ --, --C₆ H₄ O--C₆ H₄ -- or --C₆ H₄ --O--C₆ H₄ --O--C₆ H₄ -- and##STR90## wherein R⁵ is --O--, --O--(CH₂)₄ --O--, --O--(CH₂)₆ --O--,##STR91## R² is selected from the group consisting of ##STR92## whereinR⁶ is --O--, --CO--, --S--, --CH₂ --, --C(CH₃)₂, --C(CF₃)₂ --, ##STR93##or --SI(CH₃)₂ --, and ##STR94## wherein R⁷ is --O--, --SO₂ --, --CH₂ --,--CO--, --C(CH₃)₂ -- or --S--, with the proviso that when R¹ is group(i), R² is group (ii), and with the further proviso that at least one ofR¹ and R² contains a group of the formula: ##STR95## wherein X is##STR96## in which R_(f) is a perfluoroalkyl group having 1 to 10 carbonatoms, R_(f) ' is a perfluoroalkyl group having 1 to 12 carbon atoms, pis an integer of 1 to 3, q is an integer of 0 to 3, r is 0 or 1, s is aninteger of 0 to 5 and t is an integer of 0 to 5, andY is X, a hydrogenatoms, an alkyl group having 1 to 8 carbon atoms or a fluoroalkyl grouphaving 1 to 8 carbon atoms, and n is an integer not less than
 10. 2. Thesemiconductor device according to claim 1, wherein thefluorine-containing polyimide is of the formula: ##STR97## wherein X is##STR98## in which R_(f) is a perfluoroalkyl group having 1 to 10 carbonatoms, R_(f) ' is a perfluoroalkyl group having 1 to 12 carbon atonms, pis an integer of 1 to 3, q is an integer of 0 to 3, r is 0 or 1, s is aninteger of 0 to 5 and t is an integer of 0 to 5,Y is X, a hydrogen atom,an alkyl group having 1 to 8 carbon atoms or a fluoroalkyl group having1 to 8 carbon atoms, and n is an integer not less than
 10. 3. Thesemiconductor device according to claim 1, wherein thefluorine-containing polyimide is of the formula: ##STR99## wherein R¹ isas defined in claim 1, X is ##STR100## in which R_(f) is aperfluoroalkyl group having 1 to 10 carbon atoms, R_(f) ' is aperfluoroalkyl group having 1 to 12 carbon atoms, p is an integer of 1to 3, q is an integer of 0 to 3, r is 0 to 1, s is an integer of 0 to 5and t is an integer of 0 to 5,Y is X, a hydrogen atom, an alkyl grouphaving 1 to 8 carbon atoms or a fluoroalkyl group having 1 to 8 carbonatoms, and n is an integer not less than
 10. 4. The semiconductor deviceaccording to claim 1, wherein the fluorine-containing polyimide is ofthe formula: ##STR101## wherein R² is as defined in claim 19, X is##STR102## in which R_(f) is a perfluoroalkyl group having 1 to 10carbon atoms, R_(f) ' is a perfluoroalkyl group having 1 to 12 carbonatoms, p is an integer of 1 to 3, q is an integer of 0 to 3, r is 0 to1, s is an integer of 0 to 5 and t is an integer of 0 to 5,Y is X, ahydrogen atom, an alkyl group having 1 to 8 carbon atoms or afluoroalkyl group having 1 to 8 carbon atoms, and n is an integer notless than
 10. 5. A process for preparing a semiconductor device whichcomprises coating a polyamic acid of the formula: ##STR103## on asemiconductor element and lead wires and thermally curing the polyamicacid so that a resultant polyimide adheres to the semiconductor elementand lead wires, wherein R¹ is a residue which is formed by removing fourcarboxylic acid groups from an aromatic tetracarboxylic acid,R² is aresidue which is formed by removing two amino groups from an aromaticdiamine, with the proviso that at least one of R¹ and R² contains agroup of the formula: ##STR104## wherein X is ##STR105## in which R_(f)is a perfluoroalkyl group having 1 to 10 carbon atoms, R_(f) ' is aperfluoroalkyl group having 1 to 12 carbon atoms, p is an integer of 1to 3, q is an integer of 0 to 3, r is 0 to 1, s is an integer of 0 to 5and t is an integer of 0 to 5, and Y is X, a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms or a fluoroalkyl group having 1 to 8carbon atoms, and n is an integer not less than 2.